Tetrachlorofluorescein TInsP as a Substrate Analog Probe for Measuring Phytase Activity in Surface Water: Proof of Concept.

An innovative approach for measuring phytase activity (PA) in surface water is presented. A substrate analog of -inositol hexakis(dihydrogen) phosphate (InsP), commonly referred to as phytic acid, 1--5--(1-oxo-1-(2' ,4,7,7' -tetrachloro-3',6'-dihydroxy-3-oxo-3H-spiro[isobenzofuran-1,9'-xanthen]-6-yl)-5,8,11-trioxa-2-azatridecan-13-yl)-inositol 1,2,3,4,6-pentakis--(dihydrogen) phosphate, referred to as tetrachlorofluorescein (TET) tethered (T)InsP, has been developed that can be used to monitor the (phytase-catalyzed) phosphate ester bond-cleavage reaction. Test phytases, (wheat [4-] and [3-] phytase) sequentially remove phosphate groups from TET TInsP, producing dephosphorylated probe species that were readily separated by reversed-phase high-performance liquid chromatography (RP-HPLC).

Tethered phytic acid as a probe for measuring phytase activity.

A novel approach for measuring phytase activity is presented. We have developed a new chromophoric substrate analog of phytic acid, 5-O-[6-(benzoylamino)hexyl]-d-myo-inositol-1,2,3,4,6-pentakisphosphate that permits direct measurement of the phosphate ester bond-cleavage reaction using HPLC. This compound, along with its dephosphorylated T-phosphatidylinositol intermediates, are quantified using reversed phase chromatography with UV detection.

The fate of 14C-diazinon in compost, compost-amended soil, and uptake by earthworms.

A process for disposing of pesticide rinsates using sorption onto organic matter followed by composting is being evaluated. As a part of this evaluation process, we have studied the bioavailability of composted delta-2-14C-diazinon and its degradation products to earthworms (Eisenia foetida Savigny) in 30 and 60 d compost amended soil. After 60 d of composting there was considerable degradation of diazinon (95%) and a corresponding increase in the primary hydrolysis product, 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMHP) as determined by high performance thin layer chromatography (HPTLC).